Switch from scalala to breeze (allowing upgrade to Scala 2.10)

The scalala library has been abandoned, and is not available for Scala 2.10. To upgrade to Scala 2.10, the code needs instead to move to Scala Breeze (https://github.com/scalanlp/breeze). With some help from the Scala Breeze list (https://groups.google.com/forum/#!topic/scala-breeze/s-VMc76EF24) I believe I've made all the necessary changes. If there were unit tests for Convex.scala, I didn't see them, so if you have any manual testing process for this code, it would be good to try it before merging.

I'm not sure what your build environment is. I added a pom.xml and updated the Eclipse .project and .classpath files as necessary, but I didn't try to update anything else (e.g. build.xml).